Organic light-emitting element and method of producing an organic light-emitting element

ABSTRACT

An organic light-emitting component includes a substrate on which a functional layer stack is applied, the stack including a first electrode, an organic functional layer stack thereover including an organic light-emitting layer and a translucent second electrode thereover, and a translucent halogen-containing thin-film encapsulation arrangement over the translucent second electrode, wherein a translucent protective layer having a refractive index of more than 1.6 is arranged directly on a translucent second electrode between the translucent second electrode and the thin-film encapsulation arrangement, and the thin-film encapsulation arrangement is arranged directly on the translucent protective layer.

RELATED APPLICATIONS

This is a continuation of U.S. Ser. No. 14/398,821, filed Nov. 4, 2014,now U.S. Pat. No. 9,419,244, which is a §371 of InternationalApplication No. PCT/EP2013/05993 8, with an international filing date ofMay 14, 2013 (WO 2013/171209 Al, published Nov. 21, 2013), which isbased on German Patent Application No. 10 2012 208 142.9, filed May 15,2012.

TECHNICAL FIELD

This disclosure relates to an organic light-emitting component and amethod of producing an organic light-emitting component.

BACKGROUND

Organic light-emitting diodes (OLEDs) are known for lighting purposesand display applications, and typically comprise an anode on asubstrate, and a cathode thereover with, arranged between them, organiclayers comprising at least one light-emitting layer.

In OLEDs, distinction is made between those which emit light in onedirection and those which emit light in two directions. One-sideemitting OLEDs may be formed as so-called “bottom emitters” in which thelight is emitted through the substrate lying opposite the encapsulation,or as so-called “top emitters,” in which the light is emitted throughthe encapsulation. Two-side emitting OLEDs are formed simultaneously asa bottom emitter and top emitter. If all the layers of a two-sideemitting OLED are configured to be transparent, then the two-sideemitting OLED is also referred to as a transparent OLED.

Since OLEDs contain materials sensitive to corrosion, for example, dueto moisture and/or oxygen, they need to be protected by anencapsulation.

From DE 11 2009 002 034 and U.S. Pat. No. 6,692,610, for example, OLEDsare known which comprise an encapsulation consisting of a glass cover,which has a cavity in which a drying agent is arranged and which can befastened by an adhesive bead.

Furthermore, for example, from WO 2009/095006 a thin-film encapsulationwhich comprises a combination of layers applied by plasma-enhancedchemical vapor deposition (PECVD) and atomic layer deposition (ALD) isknown.

For thin-film encapsulations, starting materials (precursors) containinghalogen, which are known for a short process time, for example, BBr₃,SiCl₄, TiCl₄ and TaCl₅, are often used for production. However, due totheir breakdown products, for instance HBr in the case of BBr₃ and HClin the case of SiCl₄, TiCl₄ and TaCl₅, starting materials containinghalogen may, for example, entail damage to the cathode so that theencapsulation effect of the thin-film encapsulation may even becompletely lost. As protection against such damage to the cathode bystarting materials containing halogen, an Al₂O₃ layer is conventionallyused as an interlayer on the cathode. This layer, however, has only amoderately high refractive index of about 1.6 so that optimal lightoutput or transparency cannot be achieved in the case of OLEDsconfigured as top emitters, or to be transparent.

It could therefore be helpful to provide an organic light-emittingcomponent having a thin-film encapsulation arrangement. It could also behelpful to provide a method of producing an organic light-emittingcomponent.

SUMMARY

We provide an organic light-emitting component including a substrate onwhich a functional layer stack is applied, the stack including a firstelectrode, an organic functional layer stack thereover including anorganic light-emitting layer and a translucent second electrodethereover, and a translucent halogen-containing thin-film encapsulationarrangement over the translucent second electrode, wherein a translucentprotective layer having a refractive index of more than 1.6 is arrangeddirectly on the translucent second electrode between the translucentsecond electrode and the thin-film encapsulation arrangement.

We also provide a method of producing an organic light-emittingcomponent including providing a substrate on which a functional layerstack is applied, the stack comprising a first electrode, an organicfunctional layer stack thereover including an organic light-emittinglayer and a translucent second electrode thereover, applying atranslucent protective layer directly on the translucent secondelectrode with a halogen-free metal compound, the protective layerhaving a refractive index of more than 1.6, and applying a translucentthin-film encapsulation arrangement on the translucent protective layerwith a metal compound containing halogen.

We further provide an organic light-emitting component including asubstrate, on which a functional layer stack is applied, the stackcomprising a first electrode, an organic functional layer stackthereover including an organic light-emitting layer and a translucentsecond electrode thereover, and a translucent thin-film encapsulationarrangement over the translucent second electrode, wherein a translucentprotective layer having a refractive index of more than 1.6 is arrangeddirectly on the translucent second electrode between the translucentsecond electrode and the thin-film encapsulation arrangement.

We further yet provide an organic light-emitting component including asubstrate on which a functional layer stack is applied, the stackincluding a first electrode, an organic functional layer stack thereoverincluding an organic light-emitting layer and a translucent secondelectrode thereover, and a translucent halogen-containing thin-filmencapsulation arrangement over the translucent second electrode, whereina translucent protective layer having a refractive index of more than1.6 is arranged directly on a translucent second electrode between thetranslucent second electrode and the thin-film encapsulationarrangement, and the thin-film encapsulation arrangement is arrangeddirectly on the translucent protective layer.

We further still provide an organic light-emitting component including asubstrate on which a functional layer stack is applied, the stackincluding a first electrode, an organic functional layer stack thereoverincluding an organic light-emitting layer and a translucent secondelectrode thereover, and a translucent halogen-containing thin-filmencapsulation arrangement over the translucent second electrode, whereina translucent protective layer having a refractive index of more than1.6 is arranged directly on a translucent second electrode between thetranslucent second electrode and the thin-film encapsulationarrangement, and the protective layer consists of vanadium oxide.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 to 3 show schematic representations of method steps forproduction of an organic light-emitting component according to severalexamples.

DETAILED DESCRIPTION

Our organic light-emitting component may comprise a substrate on which afunctional layer stack having a first electrode and a translucent secondelectrode thereover is arranged. Between the first and secondelectrodes, i.e., over the first electrode and under the translucentsecond electrode, the functional layer stack comprises an organicfunctional layer stack comprising at least one organic light-emittinglayer. The term “organic functional layer stack” means all the organiclayers of the organic light-emitting component arranged between theelectrodes, while the “functional layer stack” at least also comprisesthe electrodes in addition to the organic functional layer stack. Theorganic light-emitting component may in particular be formed as anorganic light-emitting diode (OLED) comprising an electroluminescentlayer as the organic light-emitting layer.

A “translucent” layer refers to a layer which is transmissive forvisible light. The translucent layer may be transparent, i.e., clearlytranslucent, or at least partially light-scattering and/or partiallylight-absorbent so that the translucent layer may, for example, also bediffusely or milkily translucent. Particularly preferably, a layerreferred to here as translucent is formed to be as transparent aspossible so that in particular the absorption of light is as low aspossible.

Furthermore, a translucent thin-film encapsulation arrangement isarranged over the translucent second electrode. A translucent protectivelayer is arranged directly on the translucent second electrode betweenthe translucent second electrode and the translucent thin-filmencapsulation arrangement.

In a method of producing an organic light-emitting component, asubstrate may be provided having a functional layer stack whichcomprises a first electrode and a translucent second electrodethereover, between which an organic functional layer stack comprising atleast one organic light-emitting layer is arranged. Furthermore, atranslucent protective layer is applied directly on the translucentsecond electrode. In a further method step, a translucent thin-filmencapsulation arrangement is arranged on the translucent protectivelayer.

The examples and features described below apply equally for the organiclight-emitting component and for the method of producing the organiclight-emitting component.

The translucent protective layer may have a refractive index which ismore than 1.6. The refractive index data refer to the refractive indexat a wavelength of about 600 nm.

The translucent protective layer may be applied by using a halogen-freemetal compound.

The use of a halogen-free metal compound to produce the translucentprotective layer directly on the translucent second electrode may, inparticular, mean that no starting products containing halogen, inparticular no metal compounds containing halogen, are used to producethe translucent protective layer. When the translucent protective layeris applied, it is therefore possible to avoid formation ofhalogen-hydrogen compounds, for example, HBr or HCl in the case of thehalogen-containing starting materials BBr₃, SiCl₄, TiCl₄ and TaCl₅which, for example, could damage the translucent second electrode.

If the organic light-emitting component is formed as a two-side emittingtranslucent component, then the layers applied on the translucent secondelectrode, i.e., the protective layer and the thin-film encapsulationarrangement, simultaneously have the task of optical matching in respectof maximum transparency and optimization of the emission ratio betweenthe substrate-side emission and the encapsulation-side emission. In thiscase, the translucent protective layer may advantageously be provideddirectly on the translucent second electrode as a high-indexantireflection layer on which the thin-film encapsulation arrangement isthen applied. A better angle-dependent color homogeneity, or advantagesin the light output, compared to known OLEDs may, for example, also beachieved in an organic light-emitting component configured as a topemitter by the translucent protective layer with the refractive index ofmore than 1.6, due to the better antireflection properties. In bothcases, the advantageous optical properties are coupled with a goodencapsulation effect due to the thin-film encapsulation arrangementapplied on the protective layer.

It may also be particularly advantageous for the translucent protectivelayer to have a refractive index of more than 1.8, and preferably morethan 2.0.

Since, in the organic light-emitting component described here, aprotective layer having a refractive index of more than 1.6 is appliedinstead of a known Al₂O₃ interlayer, the transparency loss in thevisible wavelength range due to the Al₂O₃ layer, and an inferior outputefficiency of light due to the refractive index of Al₂O₃ being too low,can be avoided by the protective layer described here.

Furthermore, it is however possible for the thin-film encapsulationarrangement, i.e., the encapsulation layers of the thin-filmencapsulation arrangement, applied on the translucent protective layer,for example, also to be applied by using a metal compound containinghalogen, which allows efficient industrial manufacture. By virtue of thetranslucent protective layer applied halogen-free, the advantage of therapid deposition of the thin-film encapsulation arrangement usingstarting materials containing halogen can therefore still be used.

A thin-film encapsulation arrangement means a device suitable to form abarrier against atmospheric substances, in particular against moisture,oxygen and/or against further harmful substances, for instance corrosivegases, for example, hydrogen sulfide. The thin-film encapsulationarrangement may to this end comprise one or more encapsulation layers,each with a thickness less than or equal to a few 100 nm. Suitablematerials for the layers of the thin-film encapsulation arrangement are,for example, aluminum oxide, zinc oxide, zirconium oxide, titaniumoxide, hafnium oxide, tantalum oxide. Preferably, the encapsulationarrangement comprises a layer sequence having a multiplicity of the thinlayers, each of which may have a thickness of one atomic layer to 10 nm,the limits of the range indicated being included. The encapsulationarrangement may, for example, comprise at least two layers of differentmaterials. In particular, the encapsulation arrangement may alsocomprise at least three or more layers of different materials.Furthermore, the encapsulation arrangement may comprise a plurality oflayer stacks above one another, each having at least two, three or morelayers of different materials so that the encapsulation arrangement maycomprise the layers of the different materials alternately above oneanother.

In particular, the translucent protective layer may also be formed as anencapsulation layer and therefore form a first translucent encapsulationlayer over the functional layer stack directly on the translucent secondelectrode, which together with the translucent thin-film encapsulationarrangement forms an encapsulation.

Furthermore, the translucent protective layer may also comprise morethan one layer. For example, the translucent protective layer may beformed by a layer stack having at least two layers, each of which isapplied by a halogen-free metal compound. In a layer stack in which thethickness of one or all layers of the protective layer is less than thewavelength of the light emitted by the organic light-emitting component,the protective layer refractive index described here may be a refractiveindex averaged over the layers.

The translucent protective layer may be applied by an atomic layerdeposition (ALD) method. Furthermore, the thin-film encapsulationarrangement may also be applied by ALD.

ALD refers in particular to a method in which a first gaseous startingcompound is supplied to a volume in which a surface to be coated isprovided so that the first gaseous compound can adsorb on the surface.After preferably complete or almost complete coverage of the surfacewith the first starting compound, that part of the first startingcompound which is still gaseous and/or not adsorbed on the surface isgenerally removed from the volume and a second starting compound issupplied. The second starting compound is provided to react chemicallywith the first starting compound adsorbed on the surface to form a solidALD layer.

More than two starting compounds may also be used for the atomic layerdeposition.

During the atomic layer deposition, it is generally advantageous thatthe surface to be coated is heated to a temperature above roomtemperature. In this way, the reaction to form the solid ALD layer canbe thermally initiated. The temperature of the surface to be coated inthis case generally depends on the starting compounds. Furthermore, theALD method may be carried out with generation of a plasma (PEALD:“plasma-enhanced atomic layer deposition”) or in the absence of a plasma(PLALD: “plasma-less atomic layer deposition”). In respect of theconduct of the ALD method and the materials and parameters usedtherefor, reference is made to US 2011/0121354 A1, US 2011/0114992 A1and US 2011/0049730 A1, the subject matter of which is hereby explicitlyincorporated herein by reference.

The translucent protective layer may be applied, in particular by ALD,at a temperature less than or equal to 150° C., preferably less than orequal to 120° C., and particularly preferably less than or equal to 90°C. The translucent thin-film encapsulation arrangement may likewise beapplied at such a temperature. In this way, damage to or detrimentalinfluencing of the layers of the functional layer stack at highertemperatures can be avoided.

As an alternative or in addition to thin layers produced by ALD, thethin-film encapsulation arrangement may comprise at least one or amultiplicity of further layers, i.e., in particular barrier layersand/or passivation layers, deposited by thermal evaporation or by aplasma-enhanced process, for instance sputtering or PECVD. Suitablematerials therefor may be the aforementioned materials and siliconnitride, silicon oxide, silicon oxynitride, indium tin oxide, indiumzinc oxide, aluminum-doped zinc oxide, aluminum oxide as well asmixtures and alloys of those materials. The one or more furtherencapsulation layers may, for example, each have a thickness of 1 nm to5 μm, and preferably 1 nm to 400 nm, the limits of the ranges indicatedbeing included.

The translucent protective layer may comprise an oxide, in particular ametal oxide, having the aforementioned refractive index, in particularone or more of the following materials: zirconium dioxide (ZrO₂),titanium dioxide (TiO₂), zinc oxide (ZnO), hafnium dioxide (HfO₂), tindioxide (SnO₂), tantalum oxide (Ta₂O₅), vanadium oxide (V₂O₅).Accordingly, a halogen-free metal compound which contains Zr, Ti, Zn,Hf, Sn, Ta or V may advantageously be used to produce the translucentprotective layer for the method of producing the organic light-emittingcomponent.

The halogen-free metal compound may comprise a halogen-free metalorganiccompound. The halogen-free metalorganic compound may, for example,comprise tetrakis(dimethyl-amine) (TDMA) or an alcoholate, and may inparticular be a halogen-free metalorganic compound based on a TDMA or analcoholate, in particular having one of the metals Zr, Ti, Zn, Hf, Sn,Ta, V.

When using starting materials containing halogen, for example, compoundscontaining chlorine, a relative proportion of the halogen, for example,chlorine in the layer produced may be detectable by suitable measurementmethods, for example, mass spectroscopy or FIB analysis (FIB: “focusedion beam”). If, conversely, a halogen-free metal compound is used, forinstance one of those mentioned above and below, no such relativehalogen proportions can correspondingly be detected in the layerproduced. In particular, for example, it is therefore also possible todetermine whether halogen-containing or halogen-free starting materialswere used by comparing a layer produced by starting materials containinghalogen and a layer produced by halogen-free starting materials. If nohalogen, for example, chlorine is detected in a layer, then it can bededuced therefrom that a corresponding starting compound containinghalogen, for example, containing chlorine was not used in the productionthereof.

The halogen-free metal compound may in particular be formed by one ofthe following materials, for which exemplary temperatures are indicatedin brackets for ALD methods with the respectively indicated furtherstarting materials to form the materials respectively indicatedthereafter:

-   -   Hf[N(Me₂)]₄ (H₂O; 90° C.; HfO₂)    -   tetrakis(dimethylamino)tin (H₂O₂; 50° C.; SnO₂)    -   C₁₂H₂₆N₂Sn (H₂O₂; 50° C.; SnO_(x))    -   Ta[N(CH₃)₂]₅ (O₂ plasma; 100° C.; Ta₂O₅)    -   Ti [OCH(CH₃)]₄ (H₂O; 35° C.; TiO₂)    -   VO(OC₃H₉)₃ (O₂; 90° C.; V₂O₅)    -   Zn(CH₂CH₃)₂ (H₂O; 60° C.; ZnO)    -   Zn(CH₂CH₃)₂ (H₂O₂; room temperature; ZnO)    -   tetrakis(dimethylamino)zirconium (H₂O; 80° C.; ZrO₂).

For application of the translucent thin-film encapsulation arrangementhaving one or more translucent encapsulation layers on the translucentprotective layer, one of the aforementioned materials may be used.Furthermore, one of the following materials may be used, for which, asabove, exemplary temperatures are indicated in brackets for ALD methodswith the respectively indicated further starting materials to form thematerials respectively indicated thereafter:

-   -   trimethylaluminum (H₂O; 33° C., 42° C.; Al₂O₃)    -   trimethylaluminum (O₃; room temperature; Al₂O₃)    -   trimethylaluminum (O₂ plasma; room temperature; Al₂O₃)    -   BBr₃ (H₂O; room temperature; B₂O₃)    -   Cd(CH₃)₂ (H₂S; room temperature; CdS)    -   Pd(hfac)₂ (H₂, 80° C.; Pd)    -   Pd(hfac)₂ (H₂ plasma, 80° C.; Pd)    -   MeCpPtMe₃ (O₂ plasma +H₂; 100° C.; Pt)    -   MeCpPtMe₃ (O₂ plasma; 100° C.; PtO₂)    -   Si(NCO)₄ (H₂O; room temperature; SiO₂)    -   SiCl₄ (H₂O; room temperature, with pyridine catalyst; SiO₂)    -   TaCl₅ (H₂O; 80° C.; Ta₂O₅)    -   TaCl₅ (H plasma; room temperature; Ta)    -   TiCl₄ (H plasma; room temperature; Ti)    -   TiCl₄ (H₂O; 100° C.; TiO₂).

A translucent second electrode may comprise a transparent conductiveoxide or consists of a transparent conductive oxide. Transparentconductive oxides (TCOs) are transparent conductive materials, generallymetal oxides, for example, zinc oxide, tin oxide, cadmium oxide,titanium oxide, indium oxide or indium tin oxide (ITO). Besides binarymetal-oxygen compounds, for example, ZnO, SnO₂ or In₂O₃, ternarymetal-oxygen compounds, for example, Zn₂SnO₄, CdSnO₃, ZnSnO₃, MgIn₂O₄,GaInO₃, Zn₂In₂O₅ or In₄Sn₃O₁₂, or mixtures of different transparentconductive oxides, also fall within the TCO group. Furthermore, the TCOsdo not necessarily correspond to a stoichiometric composition, and theymay also be p- or n-doped.

Furthermore, the translucent second electrode may comprise a metal layeror a metal film having a metal or an alloy, for example, having one ormore of the following materials: Al, Cu, Ag, Au, Pt, Pd, Mg, Ca, Sr, Ba,Ge, Sn, Li, Sm, Y, Yb, Ti, Zr, Zn. The metal layer or the metal film hassuch a small thickness that the metal layer or the metal film is atleast partially transmissive for light.

The translucent second electrode may also comprise a combination of atleast one or more TCO layers and at least one translucent metal layer.

The materials for the translucent second electrode may be partiallyalone, in alloys or in combinations, for example, sensitively inrelation to starting materials containing halogen in deposition of alayer directly on the translucent second electrode since, during thedeposition itself and/or conversion into the final oxide by startingmaterials containing halogen, damage or modification of the secondelectrode and possibly also of further layers of the organiclight-emitting component may be caused, which influence the function ofthe component and/or by which the encapsulation effect may be destroyed.As already described above, such damage can be avoided by deposition ofthe translucent protective layer described here directly on thetranslucent second electrode by using a halogen-free metal compound.

The substrate may comprise one or more materials in the form of a layer,a plate, a sheet or a laminate, which are selected from glass, quartz,plastic, metal, silicon wafer. The substrate particularly preferablycomprises or is glass, for example, in the form of a glass layer, glasssheet or glass plate.

The substrate and the first electrode may be formed to be translucent sothat light generated in the light-emitting layer can be emitted throughthe translucent first electrode and the translucent substrate. In thiscase, the organic light-emitting component may be formed as a bottomemitter and as a top emitter or as a transparent OLED.

If the first electrode is formed to be translucent, then the firstelectrode may comprise one of the materials mentioned in connection withthe translucent second electrode, in particular a TCO. If the firstelectrode is formed to be reflective, it may, for example, comprise oneor more of the aforementioned metals with a sufficiently largethickness. As an alternative or in addition, the first electrode formedto be reflective may also comprise one or more of the aforementioned TCOmaterials.

The organic functional layer stack may comprise layers having organicpolymers, organic oligomers, organic monomers, small nonpolymericorganic molecules (“small molecules”) or combinations thereof. Inparticular, it may be advantageous for the organic functional layerstack to comprise an organic functional layer configured as a holetransport layer to allow effective hole injection into the at least onelight-emitting layer. For example, tertiary amines, carbazolederivatives, conductive polyaniline or polyethylene dioxythiophene mayprove advantageous as materials for a hole transport layer. Materialsthat exhibit radiation emission because of fluorescence orphosphorescence, for example, polyfluorene, polythiophene orpolyphenylene, or derivatives, compounds, mixtures or copolymersthereof, are suitable as materials for the at least one organiclight-emitting layer. Furthermore, the organic functional layer stackmay comprise a functional layer formed as an electron transport layer.Furthermore, the layer stack may also comprise electron and/or holeblocking layers. The organic functional layer stack may also comprise amultiplicity of organic light-emitting layers arranged between theelectrodes.

In respect of the basic structure of an organic light-emitting componentand, for example, in respect of the structure, layer composition andmaterials of the organic functional layer stack, reference is made to WO2010/066245 A1, which particularly in relation to the structure, layercomposition and the materials of an organic light-emitting component ishereby explicitly incorporated herein by reference.

The electrodes may respectively be formed over a large area. In thisway, large-area emission of the light generated in the organiclight-emitting layer can be made possible. In this case, “large area”may in particular mean that the organic light-emitting component, and inparticular the organic light-emitting layer, has an area, particularlypreferably a continuous area, greater than or equal to a few squaremillimeters, preferably greater than or equal to one square centimeter,and particularly preferably greater than or equal to one squaredecimeter.

Other advantages and refinements may be found in the following examplesdescribed in connection with the figures.

In the examples and figures, elements which are the same or of the sametype, or which have the same effect, may respectively be provided withthe same references. The elements represented and their size proportionswith respect to one another are not to be regarded as true to scale.Rather, individual elements, for example, layers, parts, components andregions, may be represented exaggeratedly large for betterrepresentation and/or for better comprehension.

FIG. 1 shows an example of a first method step of a method of producingan organic light-emitting component 100, in which a substrate 1, onwhich a functional layer stack 10 is applied, is provided.

The functional layer stack 10 comprises a first electrode 2 and a secondelectrode 3 thereover, between which an organic functional layer stack 4is arranged. The organic functional layer stack 4 comprises at least oneorganic light-emitting layer 5.

The organic functional layer stack 4 having the at least one organiclight-emitting layer 5 furthermore comprises, for example, a holeinjection layer, a hole transport layer, an electron blocking layer, ahole blocking layer, an electron transport layer and/or an electroninjection layer suitable for conducting holes and electrons to theorganic light-emitting layer 5 or blocking the respective transport.Furthermore, it is also possible for the organic functional layer stack4 to comprise a plurality of light-emitting layers. Suitable layerstructures for the organic functional layer stack 4 are known and willtherefore not be further mentioned here.

The second electrode 3, arranged lying opposite the substrate 1, isformed to be translucent and comprises, for example, one or moretranslucent metal layers, each having one or more of the followingmetals: Al, Cu, Ag, Au, Pt, Pd, Mg, Ca, Sr, Ba, Ge, Sn, Li, Sm, Y, Yb,Ti, Zr, Zn. Furthermore, as an alternative or in addition, thetranslucent second electrode 3 may comprise one or more TCOs asdescribed above in the general part, for example, ITO. The translucentsecond electrode 3 may also be formed as a multilayer electrode havingat least one or more TCO layers and at least one or more translucentmetal layers.

In the example shown, the first electrode 2 is formed as an anode andthe second electrode 3 is formed as a cathode. As an alternative tothis, the polarities of the electrodes 2, 3 may also be configured theother way round.

The layer stack formed by the substrate 1 with the functional layerstack 10 is configured as a two-side emitting transparent OLED. To thisend, in addition to the second electrode 3, the substrate 1 is alsoformed to be translucent, for example, in the form of a glass plate orglass layer, and the first electrode 2 is also formed to be translucent.The first electrode 2 comprises, for example, a transparent conductiveoxide such as, for instance, ITO or another material mentioned above inthe general part for a transparent electrode.

Alternatively, it is also possible that the layer stack formed by thesubstrate 1 and the functional layer stack 10 form an OLED configured asa top emitter. To this end, the first electrode 2 may preferably beformed to be reflective, or a reflective layer, which reflects the lightgenerated in the organic light-emitting layer 5 during operation, andemitted in the direction of the substrate 1, in the direction of thetranslucent second electrode 3, may additionally be provided on thesubstrate 1.

Since the materials for the electrodes 2, 3, in particular theaforementioned metals as well as materials of the organic functionallayer stack 4, may be sensitive to moisture, oxygen and other corrosivegases, for example, hydrogen sulfide, it is necessary to encapsulate thefunctional layer stack 10. To this end, as described in the method stepsbelow, a thin-film encapsulation arrangement 7 is applied over thefunctional layer stack 10. Since the layer stack is configured as atransparent OLED, or at least as a top emitter, besides the protectivefunction for the functional layer stack 10, the encapsulation mustsimultaneously fulfil the function of optical matching with a view tomaximum transparency and optimization of the light emission.

To attain the greatest possible leaktightness, the layers applied on thefunctional layer stack 10, which are described below, are applied by anatomic layer deposition method (ALD method). We found that, inparticular, the metals mentioned above for the translucent secondelectrode 3, as well as compounds, combinations or alloys thereof, aresensitive to starting materials containing halogen, which areconventionally used in ALD methods of producing encapsulation layers. Toensure reliable operation of the organic light-emitting component 100,however, it is necessary that the starting materials for ALD layerproduction do not damage the layers of the functional layer stack 10,and especially the translucent second electrode 3, or modify them suchthat the function of the component is influenced and/or theencapsulation effect is negated, both during the deposition and duringtheir chemical reaction to form the final oxide.

Furthermore, it is necessary for the layers applied over the translucentsecond electrode 3, in particular the layer applied directly on thetranslucent second electrode 3, to have a suitable refractive index sothat, due to antireflection properties resulting therefrom, for example,a better angle-dependent color homogeneity and/or effective light outputcan be achieved. In particular, it is advantageous for the layer applieddirectly on the translucent second electrode 3 to be configured as ahigh-index antireflection layer.

To this end, in a second method step, according to FIG. 2, a translucentprotective layer 6 is applied without intermediary and directly on thetranslucent second electrode 3 by ALD. The translucent protective layer6 has a refractive index of more than 1.6, preferably more than 1.8, andparticularly preferably more than 2.0. In the example shown, thetranslucent protective layer 6 comprises a metal oxide, preferably ZrO₂,TiO₂, ZnO, HfO₂, SnO₂, Ta₂O₅ or V₂O₅, which is applied by ALD. To notdetrimentally influence the layers of the functional layer stack 10during the ALD method, the ALD method is carried out at a temperatureless than or equal to 150° C., preferably less than or equal to 120° C.,and particularly preferably less than or equal to 90° C.

As starting materials for the translucent protective layer 6, ahalogen-free metal compound is used as a source of the metal of thetranslucent protective layer 6. To this end, halogen-free metalorganiccompounds having one of the metals Zr, Ti, Zn, Hf, Sn, Ta, V arepreferably used, in particular those based on TDMA or an alcoholate, forexample, one of the materials mentioned above in the general part whichallow ALD deposition at low temperatures, i.e., temperatures below 100°C. Thus, for example, Ti[OCH(CH₃)]₄ or Zr(N(CH₃)₂)₄ are respectivelyused as a halogen-free metal compound for deposition of TiO₂ or ZrO₂ asa translucent protective layer 6.

In a further method step, according to FIG. 3, a thin-film encapsulationarrangement 7 is deposited on the translucent protective layer 6, thisarrangement preferably likewise being applied by an ALD method at theaforementioned temperatures. Since the layers of the functional layerstack 10 are protected by the translucent protective layer 6 directly onthe translucent second electrode 3, the encapsulation layers of thethin-film encapsulation arrangement 7 may be of any desired type, and inparticular even applied, for example, by using metal compoundscontaining halogen.

If, for example, the translucent protective layer 6 is depositedhalogen-free by a titanium alcoholate to form TiO₂, the thin-filmencapsulation arrangement 7 may likewise comprise at least one or moreTiO₂ encapsulation layers, but which are applied by using TiCl₄.

Furthermore, it is also possible, for example, to deposit an aluminumtitanium oxide as an encapsulation layer of the thin-film encapsulationarrangement 7, by using trimethylaluminum and TiCl₄.

Instead of a translucent protective layer 6 which consists of TiO₂, itmay also consist, for example, of ZrO₂, which is deposited halogen-freeby using a zirconium alcoholate or TDMAZr. Furthermore, theaforementioned encapsulation layers of TiO₂ and/or aluminum titaniumoxide may be applied as the thin-film encapsulation arrangement 7 byusing metal compounds containing halogen.

Furthermore, it is also possible that, for example, HfO₂ is applied as atranslucent protective layer 6, over which one of the aforementionedthin-film encapsulation arrangements 7 is applied.

The thin-film encapsulation arrangement 7 may consist of oneencapsulation layer or comprise a multiplicity of the same or differentencapsulation layers. As an alternative to the ALD method, at least someof these may also be applied by another method, for example, by PECVD orsputtering.

In particular, the encapsulation arrangement 7 may, for example,comprise at least two layers of different materials. Furthermore, theencapsulation arrangement 7 may also comprise at least three or morelayers of different materials. Furthermore, a plurality of layer stacks,each having at least two, three or more layers of different materials,may also be arranged above one another as an encapsulation arrangement7.

The finished organic light-emitting component 100 shown in FIG. 3therefore comprises, on the substrate 1, the functional layer stack 10formed from the first electrode 2, the organic functional layer stack 4thereover comprising at least one organic light-emitting layer 5, andthe translucent second electrode 3 thereover, over which the translucentprotective layer 6 is applied directly on the translucent secondelectrode 3, the thin-film encapsulation arrangement 7 being appliedthereover, the translucent protective layer having a refractive index ofmore than 1.6.

By virtue of the method described above, it is possible to obtain anOLED as a top emitter, a two-side emitting OLED or a transparent OLED,which has a high efficiency in respect of light output, or a hightransparency, coupled with a good encapsulation effect. By introductionof the protective layer 6 applied halogen-free, the advantage of rapidALD deposition with starting materials containing halogen can still beused without damage to the layers of the functional layer stack 10occurring. In particular, the translucent protective layer 6 may also beformed as an encapsulation layer which, together with the thin-filmencapsulation arrangement 7 arranged thereover, is used forencapsulation of the functional layer stack 10.

As an alternative or in addition, the examples described in connectionwith the figures may comprise further features according to the examplesdescribed above in the general part.

By the description with the aid of examples, our elements and methodsare not restricted to the examples. Rather, this disclosure covers anynew feature and any combination of features, which includes inparticular any combination of features in the appended claims, even ifthe feature or combination is not explicitly indicated per se in theclaims or the examples.

The invention claimed is:
 1. An organic light-emitting componentcomprising a substrate on which a functional layer stack is applied, thestack comprising a first electrode, an organic functional layer stackthereover comprising an organic light-emitting layer and a translucentsecond electrode thereover, and a translucent halogen-containingthin-film encapsulation arrangement over the translucent secondelectrode, wherein a translucent protective layer having a refractiveindex of more than 1.6 is arranged directly on a translucent secondelectrode between the translucent second electrode and the thin-filmencapsulation arrangement, and the thin-film encapsulation arrangementis arranged directly on the translucent protective layer.
 2. Thecomponent according to claim 1, wherein the protective layer has arefractive index of more than 1.8.
 3. The component according to claim1, wherein the protective layer has a refractive index of more than 2.0.4. The component according to claim 1, wherein the protective layercomprises one or more selected from the group consisting of zirconiumdioxide, titanium dioxide, zinc oxide, hafnium dioxide, tin dioxide,tantalum oxide and vanadium oxide.
 5. The component according to claim1, wherein the protective layer is halogen-free.
 6. The componentaccording to claim 1, wherein the substrate and the first electrode aretranslucent.
 7. The component according to claim 1, wherein theprotective layer is formed as layer stack with at least two layers, eachof said layers being halogen-free.
 8. An organic light-emittingcomponent comprising a substrate on which a functional layer stack isapplied, the stack comprising a first electrode, an organic functionallayer stack thereover comprising an organic light-emitting layer and atranslucent second electrode thereover, and a translucenthalogen-containing thin-film encapsulation arrangement over thetranslucent second electrode, wherein a translucent protective layerhaving a refractive index of more than 1.6 is arranged directly on atranslucent second electrode between the translucent second electrodeand the thin-film encapsulation arrangement, and the protective layerconsists of vanadium oxide.
 9. An organic light-emitting componentcomprising a substrate on which a functional layer stack is applied, thestack comprising a first electrode, an organic functional layer stackthereover comprising an organic light-emitting layer and a translucentsecond electrode thereover, and a translucent halogen-containingthin-film encapsulation arrangement over the translucent secondelectrode, wherein a translucent protective layer having a refractiveindex of more than 1.6 is directly arranged on a translucent secondelectrode between the translucent second electrode and the thin-filmencapsulation arrangement, the thin-film encapsulation arrangement isarranged directly on the translucent protective layer, and thetranslucent protective layer consists of vanadium oxide.